2003 Honda Element Replacing my Radiator & Radiator Fan

I had front end damage to my Honda element recently and I have replaced my Radiator & the Radiator fan. If I have properly installed my radiator fan would the fan ever come off or become loose? Because my fan come off after it was installed and went through my radiator while I was driving on the highway. Did I do something wrong? The bolts came off (that tightens down the radiator fan). Please help me out! Thanks for your time!